Thougts about creating a Oasis
If a player X dies, every other player can find his grave and sacrifice water and fruits on his grave.
when enough scarifices are made, the player x can revisit his grave and use a sign/rune to create a oasis.
The rune is then depleted.
Graves with scarifices are sinking slower. If there are many graves toghether or near of oasis the graves will sink and vanish a lot faster.
raiding a grave destroys it.
This generates a dynamic where players are searching graves for sacrificing fruits and searching their own graves for founding an oasis.